Background and Basis of Presentation	6 Months Ended
Jun. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	Background and Basis of Presentation The Federal Home Loan Bank of Chicago is a federally chartered corporation and one of 11 Federal Home Loan Banks (the FHLBs) that, with the Office of Finance, comprise the Federal Home Loan Bank System (the System). The FHLBs are government-sponsored enterprises (GSEs) of the United States of America and were organized under the Federal Home Loan Bank Act of 1932, as amended (FHLB Act), in order to improve the availability of funds to support home ownership. We are supervised and regulated by the Federal Housing Finance Agency (FHFA), an independent federal agency in the executive branch of the United States (U.S.) government. Each FHLB is a privately-capitalized, member-owned cooperative with members from a specifically defined geographic district. Our defined geographic district is Illinois and Wisconsin. All federally insured depository institutions, insurance companies engaged in residential housing finance, credit unions and community development financial institutions located in our district are eligible to apply for membership with us. All our members are required to purchase our capital stock as a condition of membership. Our capital stock is not publicly traded, and is issued, repurchased or redeemed at par value, $100 per share, subject to certain statutory and regulatory limits. As a cooperative, we do business with our members, and former members (under limited circumstances). Specifically, we provide credit principally in the form of secured loans called advances. We also provide liquidity for home mortgage loans to members approved as Participating Financial Institutions (PFIs) through the Mortgage Partnership Finance® (MPF®) Program. Our accounting and financial reporting policies conform to generally accepted accounting principles in the United States of America (GAAP). In the opinion of management, all normal recurring adjustments have been included for a fair statement of this interim financial information. These unaudited condensed financial statements and the accompanying notes should be read in conjunction with the audited financial statements and footnotes for the year ended December 31, 2024, included in our 2024 Annual Report on Form 10-K (2024 Form 10-K) starting on page F-1, as filed with the Securities and Exchange Commission (SEC). Unless otherwise specified, references to we, us, our, and the Bank are to the Federal Home Loan Bank of Chicago. “Mortgage Partnership Finance”, “MPF”, “MPF Xtra”, "Downpayment Plus", "DPP", Downpayment Plus Advantage", "DPP Advantage", and "Community First" are federally registered trademarks of the Federal Home Loan Bank of Chicago. Refer to the Glossary of Terms starting on page 61 for the definitions of certain terms used herein. Use of Estimates and Assumptions We are required to make estimates and assumptions when preparing our condensed financial statements in accordance with GAAP. The most significant of these estimates and assumptions applies to fair value measurements, which includes derivative instruments. Our actual results may differ from the results reported in our condensed financial statements due to such estimates and assumptions. This includes the reported amounts of assets and liabilities, the reported amounts of income and expense, and the disclosure of contingent assets and liabilities. Basis of Presentation The basis of presentation pertaining to our single reportable operating segment and chief operating decision-maker has not changed since we filed our 2024 Form 10-K. The basis of presentation pertaining to the consolidation of our variable interest entities has not changed since we filed our 2024 Form 10-K. The basis of presentation pertaining to our gross versus net presentation of derivative financial instruments also has not changed since we filed our 2024 Form 10-K. Refer to Note 1 - Background and Basis of Presentation to the financial statements in our 2024 Form 10-K with respect to our basis of presentation for single reportable operating segment, consolidation of variable interest entities and our gross versus net presentation of financial instruments for further details.

The Federal Home Loan Bank of Chicago is a federally chartered corporation and one of 11 Federal Home Loan Banks (the FHLBs) that, with the Office of Finance, comprise the Federal Home Loan Bank System (the System). The FHLBs are government-sponsored enterprises (GSEs) of the United States of America and were organized under the Federal Home Loan Bank Act of 1932, as amended (FHLB Act), in order to improve the availability of funds to support home ownership. We are supervised and regulated by the Federal Housing Finance Agency (FHFA), an independent federal agency in the executive branch of the United States (U.S.) government.

Each FHLB is a privately-capitalized, member-owned cooperative with members from a specifically defined geographic district. Our defined geographic district is Illinois and Wisconsin. All federally insured depository institutions, insurance companies engaged in residential housing finance, credit unions and community development financial institutions located in our district are eligible to apply for membership with us. All our members are required to purchase our capital stock as a condition of membership. Our capital stock is not publicly traded, and is issued, repurchased or redeemed at par value, $100 per share, subject to certain statutory and regulatory limits. As a cooperative, we do business with our members, and former members (under limited circumstances). Specifically, we provide credit principally in the form of secured loans called advances. We also provide liquidity for home mortgage loans to members approved as Participating Financial Institutions (PFIs) through the Mortgage Partnership Finance® (MPF®) Program.

In the opinion of management, all normal recurring adjustments have been included for a fair statement of this interim financial information. These unaudited condensed financial statements and the accompanying notes should be read in conjunction with the audited financial statements and footnotes for the year ended December 31, 2024, included in our 2024 Annual Report on Form 10-K (2024 Form 10-K) starting on page F-1, as filed with the Securities and Exchange Commission (SEC).

“Mortgage Partnership Finance”, “MPF”, “MPF Xtra”, "Downpayment Plus", "DPP", Downpayment Plus Advantage", "DPP Advantage", and "Community First" are federally registered trademarks of the Federal Home Loan Bank of Chicago.

We are required to make estimates and assumptions when preparing our condensed financial statements in accordance with GAAP. The most significant of these estimates and assumptions applies to fair value measurements, which includes derivative instruments. Our actual results may differ from the results reported in our condensed financial statements due to such estimates and assumptions. This includes the reported amounts of assets and liabilities, the reported amounts of income and expense, and the disclosure of contingent assets and liabilities.

The basis of presentation pertaining to our single reportable operating segment and chief operating decision-maker has not changed since we filed our 2024 Form 10-K. The basis of presentation pertaining to the consolidation of our variable interest entities has not changed since we filed our 2024 Form 10-K. The basis of presentation pertaining to our gross versus net presentation of derivative financial instruments also has not changed since we filed our 2024 Form 10-K. Refer to Note 1 - Background and Basis of Presentation to the financial statements in our 2024 Form 10-K with respect to our basis of presentation for single reportable operating segment, consolidation of variable interest entities and our gross versus net presentation of financial instruments for further details.